How Does the Soil Chemical Composition Affect Its Cross-sections, Effective Atomic Number and Electron Density? Computer Simulation Analysis to Highlight the Radiation-soil Interaction Processes

The study of radiation interaction parameters in complex materials (e.g., soils) has gained great importance in the last decades. However, few studies have directly addressed in detail how the radiation interaction is affected by the chemical and physical characteristics of soils, especially in tropical and subtropical climate regions like Brazil. The soil is an important material widely utilized in agriculture and engineering. Knowing this material radiation interaction properties is fundamental to understand its role in different areas of applied sciences such as radiation shielding, environmental monitoring, and geological characterization. This study presents a detailed analysis of how parameters like the atomic ( σ_A ), molecular ( σ_M ), and electronic ( σ_E ) cross-sections are affected by the texture and chemical composition of soils. The effective atomic number ( Z_eff ) and electron density ( N_el ) were also investigated. Photon energies in the energy range from 10 to 1330 keV were selected. The XCOM computer code was chosen to simulate the radiation interaction parameters. Five soils presenting different physical characteristics and oxide compositions were studied. The results show a strong dependence of the radiation interaction parameters on the elemental composition up to 100 keV . After this photon energy, factors such as fractional abundance, for example, become important to discriminate the soils. The parameters σ_A , σ_E , and Z_eff followed the same trend as that of the percentage of the oxides Fe_2O_3 and TiO_2 among soils, while σ_M and N_el matched the oxides SiO_2 and Al_2O_3 . Our results highlight that understanding how the chemical composition influences the radiation interaction in complex materials provides information that can be useful in areas such as radiation shielding and image analysis and processing, which are based on radiation interaction data.